Certain alkane alcohols, such as hexanediols, are valuable intermediate products in the chemical industry. 1,6 Hexanediol finds application in a variety of polymeric systems and can be used in the synthesis of specialty chemicals. The terminal location of the hydroxyl groups of 1,6 hexanediol results in a rapid and simultaneous reaction in the formation of numerous disubstituted products.
1,6 Hexanediol is used in the production of polyesters for polyurethane elastomers, coatings, adhesives, and polymeric plasticizers. In these end-use areas, it contributes significantly to many high-performance characteristics such as hydrolytic stability, high flexibility, good adhesion and surface hardness.
Cyclohexanediols, especially the 1,4 cis and 1,4 trans forms, constitute impurities in hexanediol production processes. The presence of the cyclic diols may reduce flexibility of coatings prepared from resins resulting from the reaction of hexanediols with acids. Uneven distribution of cyclohexanediols in the resin can also result in the uneven distribution of cyclohexanediol polymers and thus the potential for slightly different properties in various parts of the resulting resin. Removal of cyclohexanediols allows formation of a more consistent resin.
Prior to the present invention, difficulties were encountered in removing, for example, cycloalkanediols from compositions comprising the linear counterparts. The difficulties resulted from the fact that the boiling points of the linear and cyclic forms are sufficiently similar to make separation by distillation difficult. The present invention overcomes that problem by providing a method of converting, for example, a cyclic alkanediol to a compound having a boiling point that is sufficiently different from that of the corresponding linear alkanediol to permit separation by distillation.